Electromagnetically operated switch

Abstract

An electromagnetically operated switch comprises a cylindrical bobbin having an exciting coil wound thereon; a fixed core arranged in the bobbin and a movable core arranged to confront the fixed core; a flange provided on the fixed core to expand outwardly in the radial direction and located on an end surface of the bobbin; a rod inserted in a through bore formed in the center of the fixed core; a flexible insulating sheet put on the end surface of the flange of the fixed core, having an opening in a central portion, and connected sealingly to the rod which extends through the opening; a cup-shaped cap mounted on the flange end surface to sandwich the sheet between the flange and the cap; and a movable contact supported by the rod in the cap.

What is claimed is: 
     
       1. An electromagnetically operated switch comprising: a cylindrical bobbin having an exciting coil would thereon;   a fixed core arranged in the bobbin and a movable core arranged to confront the fixed core;   a flange provided on the fixed core to expand outwardly in the radial direction and located on an end surface of the bobbin;   a rod inserted in a through bore formed in the center of the fixed core;   a flexibly insulating sheet put on the end surface of the flange of the fixed core, having an opening in a central portion, and connected sealingly to the rod which extends through the opening, wherein said sheet is provided with an air bleed aperture;   a cup-shaped cap mounted on the flange end surface to sandwich the sheet between the flange and the cap; and   a movable contact supported by the rod in the cap.   
     
     
       2. A switch according to claim 1, wherein the sheet is of rubber. 
     
     
       3. A switch according to claim 1, wherein the marginal edge of the sheet is sandwiched at the location where the open end of the cap and the flange end surface of the fixed core are in contact with each other. 
     
     
       4. A switch according to claim 1, wherein the sheet has slack in a portion near to the peripheral edge. 
     
     
       5. A switch according to claim 1, wherein the sheet has its central portion integrally provided with a supporter for supporting the movable contact. 
     
     
       6. A switch according to claim 1, wherein the aperture is formed at a position closest to the center of the sheet.